Drip Pump System and Method

ABSTRACT

A system and method for pumping an underground drip includes a pump barrel housing with a plunger and an elongated stroke actuator cylinder sealed to the pump barrel that vertically reciprocates the plunger. The pump barrel and plunger are preferably vented to avoid vacuum lock during pumping. The plunger pumps the fluid located in the drip upwardly to a low pressure tank or a pressurized surface vessel. A ball valve may be screwed onto the siphon line to allow for insertion and removal of the pump barrel and seals the siphon line if the pump is removed. A stuffing box seals the pump barrel to the upper end of the siphon line to prevent air from entering the system. The stuffing box also allows the pump depth to be easily adjustable by sliding the pump in until the pump tags bottom and then tightening at any point needed.

FIELD OF INVENTION

This invention relates generally to gas gathering and transportationsystems and, in particular, the extraction of fluid out of gas gatheringand transportation pipelines.

BACKGROUND OF THE INVENTION

In gas gathering and transportation systems, fluid in pipelines has beena constant source of problems and expense. In depleted fields inparticular, where wells must be pulled down to a few pounds or a vacuumto maintain production, the problem is worse. For many years the amountof vacuum was limited due to the use of compressors which leak oxygenpast mechanical seals and rings. The advent of liquid ring and rotaryliquid screw type compressors supplied the industry with the ability toincrease production in the Panhandle West gas fields, and many otherfields, by reducing the pressure below atmospheric without introducingoxygen into the system. Over the past 20 years this has led to entirefields involving thousands of wells which must be kept at variousvacuums, with many at 22″, which is close to the maximum that can bereached at the elevation of the Panhandle West fields.

A method to extract fluid out of these lines has remained many yearsbehind the technology used to place them in the existing situation. Asthe secondary recovery technique progressed, the time increased forwells and gathering lines to pressure up and blow the fluid out of thedrips when the compressors were shut down or bypassed. (A “drip” istypically an underground vessel designed to catch and hold fluids whichdrop out of natural gas during transportation through pipelines). Overthe past several years the situation has evolved into a major problem.Drip trucks cannot pull fluid out unless the system is vented or leftdown for long periods of time in order to lower the amount of vacuum. Inmany cases entire sections of a field involving several wells must beshut down and lines allowed to suck in air. After a point is reachedwhere a truck can empty the drip, the wells are opened and lines purgedto atmosphere to evacuate the oxygen which was sucked in.

The wasted power for compressors, the amount of gas lost with air duringthe purging process, and the hours of trucking cost and down time areunacceptable. The danger of environmental impact problems due to thewasted natural gas is increasing because the oxygen tends to lay in thelow parts of the lines and a large amount of gas must be vented toattain the 50 ppm or less oxygen content required to enter the pipelinesystem and resume normal production delivery. Many of these wells willnot return to positive pressure in several months or years. Even innewer wells, gas is wasted and the environment is impacted as thousandsof mcf are lost daily to the atmosphere when vacuum trucks or gear typepumps are used to load the drip trucks.

One of the insurmountable problems with all prior art is the mixture ofthe fluid in these drips. The fluid is a high gravity condensate mixedin various degrees of percentage with water. Pumps used to move normalliquefied petroleum gas or Y-Grade products are damaged or unsuitablefor moving water and heavier liquids. Pumps used to move fluids are notcapable of moving the Y-Grade type hydrocarbons. Vacuum type pumps arelimited to the same or less vacuum capability as the elevation of thegathering system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is view of a closed system for pumping fluid from an undergrounddrip. A pump barrel is in communication with a fluid collecting withinthe underground drip. A stuffing box helps provide for verticaladjustment of the pump barrel so that the nipple end of the pump tags abottom of the drip. A vertically positioned elongated stroke actuatorcylinder supported above the pump barrel actuates a piston incommunication with the pump plunger to force fluid upward into a teefitting and to a collection vessel.

FIG. 2 is a view of the pumping system in which a pumping tee is screweddirectly to the siphon line. Valving on the pumping tee allows the dripto be sucked out or blown in a normal way if the pump is not working.

FIGS. 3A and 3B are a view of the pumping system in which a ball valveis connected above the pumping tee and the stuffing box is screwed intothe ball valve. When the pump pulled, the ball valve may be closed priorto clearing the stuffing box and the pumping system does not have to beshutdown if repairs are needed.

FIGS. 4A and 4B are a view of a stuffing box-free pumping system. Toensure that the straining nipple tags the bottom of the pump, the pumpbarrel and piping must be cut to exact length pipe.

FIG. 5 is a view of a power source for the pumping system. On manyremote locations solar power panels may be used as the power source. Inaddition, if a hydraulic cylinder is used as the stroke actuatorcylinder, the hydraulic fluid pump system may include a hydrauliccontrol.

BRIEF SUMMARY OF THE INVENTION

A system and method for pumping fluid out of an underground dripincludes a pump barrel in communication with a fluid collecting withinthe underground drip. The drip may have a positive pressure or may havea vacuum within. A vertically positioned elongated stroke actuatorcylinder is supported above the pump barrel and in alignment therewith.

The pump barrel may be located within a portion of an existing siphonline. The system may also include a ball valve that receives the pumpbarrel and sealably closes access to an upper end of the siphon line.The pump barrel may also have at least one vent port and include aplunger having at least one vent hole and one or more traveling valves.

The stroke actuator cylinder may be a hydraulic cylinder, an aircylinder, a vacuum cylinder, an electric cylinder, or an electromagneticcylinder, and includes a vertically displaceable piston that is incommunication with the pump plunger. The stroke actuator cylinder mayalso include a seal member affixed to a lower end of the cylinder forsealably and reciprocally receiving a piston rod.

A power system powers the stroke actuator cylinder to verticallyreciprocate the piston and thereby the plunger. Fluid flows upwardlyunder pressure through a passageway formed by the pump barrel and into atee fitting vertical passageway and out through the tee fitting sideopening to a collection vessel. The collection vessel may be a lowpressure tank or a surface pressurized tank and may have a vapor returnline in communication with the underground drip. The pump, strokeactuator cylinder, tee fitting, and collection vessel form a closedsystem. A water collection tank may also be included.

The system may include a stuffing box that allows for vertical heightadjustment of the pump barrel and piping. The stuffing box is mounted onthe siphon line and then the pump barrel is inserted through the siphonline until the straining nipple of the pump tags a bottom portion of thedrip. Stuffing box is then tightened to seal the pump barrel to thesiphon line to prevent air from entering the drip.

The method of pumping the underground drip includes the step ofinserting the pump barrel into the drip until the straining nipple endof the pump barrel tags a bottom portion of the drip. The pump barrel issealed at an upper end and the elongated stroke actuator cylinder ispositioned and sealed above and in alignment with the pump barrel. Acollection vessel is connected to a tee fitting in communication withthe pump barrel. A plunger within the pump barrel is then sequentiallyvertically manipulated by the stroke actuator cylinder to pump fluidlocated within the underground drip to the collection vessel.

The method may also include the step of inserting and passing the pumpbarrel through an open ball valve attached to an upper end of a siphonline. The pump barrel may then be removed from the siphon line and theball valve closed. A draining step may be accomplished by a tee with avalve located below the ball valve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Elements of the preferred embodiments illustrated by the drawings anddescribed herein are referenced by the following numbers:

10 Drip pumping system 12 Siphon line 14 Ball valve 16 Fluid outlet tee17 Thread adaptor 18 Top of 16 20 Stroke actuator cylinder 22 Top end 24Bottom end 26 Piston 28 Interior wall 30 Piston rod 32 Seal member 34Closure member 36 Water tank 38 Hydraulic fluid pump 40 Pipe 42 Inletopening 44 Return pipe 45 Outlet opening 46 Prime mover 48 Battery 50Hydraulic control 52 Vertical passageway 54 Pump 56 Side opening 58 Rod60 Stuffing box 62 Valve and gauge 64 Collection line 66 Collectionvessel 68 Back pressure valve 70 Return line 72 Pump barrel 74 Lower end76 Standing valve 78 Straining nipple 82 Traveling valve 84 Travelingvalve 88 Vent 92 Plunger 94 Lower portion 96 Upper portion 97 Plungertube 98 Vent hole 100 Drip 102 Inlet end 104 Outlet end 106 Low point inpipeline P 108 Pipe 110 Bottom portion of 100 112 Solar panel 114Pumping tee & valving 116 Hammer union half 118 Half-union 120 Nipple122 Nipple

Referring first to FIGS. 1 and 2, pumping system 10 includes a strokeactuator cylinder 20 in communication with a pump 54. Stroke actuatorcylinder 20 is preferably a non-vented hydraulic cylinder similar to thehydraulic cylinder disclosed in my U.S. patent application Ser. No.11/103,067, filed on Apr. 11, 2005 (U.S. Patent Application Pub. No.2006/0171821, published Aug. 3, 2006), but may be an air, gas, vacuum,or non-hydraulic fluid linear actuator. Pump 54 may be inserted intosiphon line 12, which has its lower end located at a bottom portion 110of drip 100. Alternatively, pump 54 may be inserted through a fittingwith no siphon line 12 or pipe extending to drip 100. The pump barrel 72(see FIG. 3) replaces the need for siphon line 12 other than for blowingdrip 100 if pump 54 is removed for a period of time.

Pump 54 may be a standard tubing pump or an insert pump but ispreferably a gas vent pump as disclosed my U.S. patent application Ser.No. 11/092,258, filed Mar. 29, 2005 (U.S. Patent Application Pub. No.2005/0226752, published Oct. 13, 2005). Pump 54 includes a pump barrel72 and a plunger 92. Plunger 92, which is of a type well-known in theart, contains one or more traveling valves 82, 84 and pump barrel 72contains a standing valve 76. See FIGS. 3 & 4. In a preferredembodiment, plunger 92 is a metal plunger, however, because of therelatively low load on pump 54, lower plunger portion 94 and upperplunger portion 96 are preferably elastomeric cup-type plungers. Indrips 100 having 21-to-22 inches of vacuum, experiments showed that itis mandatory for lower plunger portion 94 to be an elastomeric cup-typeplunger and preferably a positive seal ring-type plunger.

A standard pump 54 might prove adequate in some drips 100 that are onpositive pressure. In other drips 100, a gas vent pump 54, whichincludes a pump barrel 72 having vent ports 88 (see FIGS. 3 & 4), may beneeded due to vacuum lock between the standing valve 76 and travelingvalve 82 of a standard pump 54. As explained in my U.S. PatentApplication No. 60/562,207, at the top of each upstroke of pump 54 thecompression in the chamber of pump 54 equalizes with conditions existingin drip 100. Fluid flows readily into pump 54 and is displaced on thedownstroke. Because of the relative shallow depths of most drips 100,only one travelling valve 82 may be required in the gas vent pump 54. Inhigh vacuum applications, the vent hole 94 in plunger 92, if used,preferably aligns with vent ports 88 at the bottom of the downstroke ofgas vent pump 54. In addition, a second travelling valve 84 may berequired.

Returning to FIGS. 1 and 2, drip 100 may be a horizontal drip or avertical drip. In a preferred embodiment, drip 100 is interspersedbetween a downstream and upstream portion of pipeline P. The upstreamportion is connected to an inlet end 102 and the downstream portion isconnected to an outlet end 104 of drip 100. In another preferredembodiment, a low point 106 of the pipeline P where fluid (high gravitycondensate and water) settles is tapped into and connected by way ofpiping 108 to inlet end 102 of drip 100.

The high gravity condensate and water being pumped from drip 100 by pump54 enters a tee fitting 16 and is delivered under pressure to acollection vessel 66. Collection vessel 66 is preferably a Y-gradepressure tank that includes a back pressure valve 68 and a return line70 to pipeline P. Any suitable collection vessel, however, may be usedfor collection vessel 66. Collection vessel 66 may employ separationmethods well-known in the art for separating the water from the highgravity condensate. Positive pressure means may be used to transport theseparated water components to a water tank 36 for storage and furtherprocessing.

Referring to FIGS. 3 and 4, tee fitting 16, thread adaptor 17, and endgland seal member 32 may be affixed to pump barrel 72 (see FIG. 3). Teefitting 16 has a vertical through passageway 52 and a side opening 56.Tee fitting 16 is preferably a male or female threaded pump barrelcoupling connecting stroke actuator cylinder 20 directly to pump barrel72. A threaded hole in the side of tee fitting 16 forms side opening 56for fluid discharge out of the upper portion of pump barrel 72 above theplunger 92 and into collection vessel 66. Seal member 32, which servesas a hydraulic end gland seal, may be incorporated into the top end 18of tee fitting 16. Seal member 32 is designed to capture hydraulic fluidin the closed drip pumping system 10 in the event of seal failure andprotect the environment. Because pump 54 is primarily designed tooperate in a vacuum situation, there is a greatly reduced probability ofspillage of hydrocarbons or hydraulic oil. If the seals fail, all fluidswill be sucked back into drip 100.

In a preferred embodiment, a stuffing box 60 is mounted on siphon line12 and then pump barrel 72 is inserted through siphon line 12 until thestraining nipple 78 of pump 54 tags a bottom portion 110 of drip 100.Stuffing box 60 is then tightened to seal pump barrel 72 to siphon line12 to prevent air from entering drip 100. In cases involving a 2″ siphon12, it is preferable to use a 1¾ inch stuffing box 60 and a 1½ inch pumpbarrel 72.

Alternately, a ball valve 14 may be screwed directly to a pumping tee114 which, in turn, is screwed directly to siphon line 12. Valving onpumping tee 114 allows drip 100 to be sucked out or blown in a normalway if pump 54 is not working. As stated previously, drip 100 may beemptied with or without pump 54 being in siphon line 12. Stuffing box 60is screwed into ball valve 14. Pump barrel 72 then slides through ballvalve 14 and stuffing box 60. When pump 54 is pulled, ball valve 14 maybe closed prior to clearing stuffing box 60 and pumping system 10 doesnot have to be shutdown if repairs are needed. A modified stuffing boxwith a clapper stop (normally used in oil wells in the event of apolished rod part) may be used as stuffing box 60 to make installationand removal simple.

Stuffing box 60 is a means to prevent air from being sucked into drip100 from the surface and down into the space between siphon line 12 andthe pump barrel 72. Stuffing box 60 also enables the use of one lengthof pump barrel 72 to be used and sealed at any point along the barrel72. The portion of pump barrel 72 and stroke actuator cylinder 20 thatlies above stuffing box 60 depends on the length of the pump barrel 72relative to the depth of drip 100.

In another preferred embodiment, to accomplish sealing integrity to thesiphon line 12, a half union 116 may be installed on siphon line 12 anda hammer union 118 may be attached directly to pump barrel 72.Alternately, ball valve 14 may be used in a manner similar to that asdescribed above. The hammer union 118 confines the pumped condensate andwater to the interior of pump barrel 72 and tee fitting 16. Seal member32 precludes fluid from drip 100 from entering the hydraulic system.

Use of unions 116 and 118 eliminates the requirement for stuffing box60. This stuffing box free arrangement and importance of seal member 32is described in further detail in my U.S. patent application Ser. No.11/103,067, filed on Apr. 11, 2005. The hammer union attachment method,however, is not adjustable. The pump barrel 72 and piping (e.g., nipples120, 122), therefore, must be cut to an exact length (see FIGS. 4A & B).

Supported on the top 18 of tee fitting 16 and in direct connection topump barrel 72 is the vertically positioned elongated stroke actuatorcylinder 20. Cylinder 20 provides vertical reciprocation of plunger 92.Although vertical reciprocation may be accomplished by air, gas, vacuum,electric or electromagnetic linear actuator and other prime movers—suchas water, antifreeze or other fluids to further reduce environmentalconcerns—hydraulic force is still the preferred method at this time.Cylinder 20, therefore, is preferably a hydraulic cylinder.

Hydraulic cylinder 20 has a top end 22 and a bottom end 24. A piston 26is vertically and slideably displaceable within the internal cylindricalwall 28 of hydraulic cylinder 20. Affixed to piston 26 is a vertical,downwardly extending piston rod 30. Piston rod 30 is received into theinterior of pump barrel 72. To close the bottom end 24 of hydrauliccylinder 20, a seal member 32 that slideably and sealably receivespiston rod 30 is preferred. The top end 22 of hydraulic cylinder 20receives a closure member 34 to provide sealing integrity for hydrauliccylinder 20.

A hydraulic fluid pump system 38 has a high pressure fluid outlet thatis connected by pipe 40 to an inlet opening 42 in the cylindrical wallof hydraulic cylinder 20. Return pipe 44 connects to an outlet opening45 in the sidewall of hydraulic cylinder 20. As shown in FIG. 5, thehydraulic fluid pump system 38 includes a prime mover 46, such as anengine or electric motor, by which pump 38 is powered. If prime mover 46is a motor, energy may be supplied by way of a battery 48 that isrepresentative of any other kind of electrical energy source. Inaddition to electric over hydraulic valves, it is also possible toreverse motor rotation when reciprocating the stroke actuator cylinder20. By eliminating the need for electric valves, the cost to build andmaintain pumping system 10 is reduced and problems and down time causedby valve failure is eliminated. On many remote locations solar powerpanels 112 may be used as the power source. In addition, hydraulic fluidpump system 38 may include hydraulic control 50 by which the force ofhydraulic fluid applied to move piston 26 is controlled. Hydrauliccontrol 50 may be a variable control, thereby allowing for a variableupstroke and downstroke sequence of stroke actuator cylinder 20.

Because of the relatively shallow depth of most drips 100, an adaptor 58may be used to connect the piston rod 30 directly to the plunger 92rather than requiring a rod string (not shown) or long pump (not shown).As stroke actuator cylinder 20 vertically reciprocates, pump 54 pumpsthe high gravity condensate and water upwardly from a bottom portion 110of drip 100 within pump barrel 72. The high gravity condensate and waterenter into pump barrel 72, which is in direction connection to teefitting 16. A side opening 56 in tee fitting 16 provides a way ofchanneling the pumped condensate and water to a collection line 64 incommunication with collection vessel 66. A valve and gauge 62 may beused to monitor and check the action of pump 54 and the flow ofcondensate and water into collection line 64.

In a test application of pumping system 10, a pumping system 10 wasinstalled on a Pioneer Natural Resources' (PNR) drip located in thePanhandle West fields. This particular drip represented a difficultapplication—an increase of well backpressure, caused by the drip fillingwith fluid of 3 inches less vacuum, caused a loss of 100 mcf per day—andPNR had been on a 5-year project focused on improved methods of removingfluid from this drip. Pumping system 10 was applied and it removed thehigh gravity condensate and water from the drip under previouslyimpossible pumping conditions. Compressed air was the most availableprime mover and a vent pump 54 was able to accomplish fluid loading at18.5 inches of vacuum and reach approximately 800 psi discharge pressurewith about 68 psi air pressure on the stroke actuator cylinder 20. Thetest proved that pumping system 10 is capable and readily available tosolve the existing problems mentioned in the background section of thisapplication, as well as provide an improved method of removing fluidfrom pipelines. This method includes elimination of criticalenvironmental and clean air issues as well as waste of natural resourceswhich could lead to State mandatory installation rules.

Pumping system 10 allows for drips 100 to be pumped directly into lowpressure collection vessels 66. More importantly, drips 100 can bepumped into surface pressurized tanks 66 and the water can be removed bypositive tank pressure into normal water tanks 36 with no gas lost toatmosphere. The pure Y-Grade product can be stored and loaded byliquefied petroleum gas trucks with no loss to atmosphere during thetrucking process.

Pumping system 10 may be employed to pump drips 100 without any lostproduction time. Field production may 100 be increased by keeping dripspumped out and gathering line pressure constant on the entire field. Inmany applications, drips can be pumped directly from gathering lines inclose proximity to gas discharge lines or oil flow lines, even at highpressures. Where paraffin in oil flow lines and low gravity oil isinvolved, pumping system 10 will help keep flow lines clear or reducepressure problems. A hole digger (not shown) may be used to quicklyinstall a vertical drip 100.

While pumping system 10 has been described with a certain degree ofparticularity, many changes may be made in the details of constructionand the arrangement of components without departing from the spirit andscope of this disclosure. The pumping system, therefore, is not limitedto the embodiments set forth herein for purposes of exemplification, butis to be limited only by the scope of the attached claim or claims,including the full range of equivalency to which each element thereof isentitled.

1-17. (canceled)
 18. A method of pumping an underground drip comprisingthe steps of: inserting a pump barrel into an underground drip until astraining nipple end of the pump barrel tags a bottom portion of theunderground drip; sealing the pump barrel at an upper end of the pumpbarrel; positioning and sealing an elongated stroke actuator cylindersupported above and attached to the pump barrel and in alignmenttherewith; connecting a collection vessel to a tee fitting incommunication with the pump barrel; sequentially vertically manipulatinga plunger within the pump barrel and in communication with the strokeactuator cylinder to pump a fluid located within the underground drip tothe collection vessel.
 19. A method according to claim 18 wherein saidstep of inserting further comprises the step of passing the pump barrelthrough an open ball valve attached to an upper end of a siphon line.20. A method according to claim 19 further comprising the steps ofremoving the pump barrel from a siphon line and closing an open end ofthe siphon line.
 21. A method according to claim 20 further comprisingsaid closing step including shutting the open ball valve attached to theupper end of the siphon line.
 22. A method according to claim 20 furthercomprising a draining step, said draining step being accomplished by atee with a valve located below the ball valve.